(1) Field of the Invention
This invention relates generally to dental veneers for attachment to the labial enamel surfaces of human teeth. More specifically, it is concerned with the provision and application of dental veneers composed of precious metals.
(2) Description of the Prior Art
The use of precious metal crowns for aesthetic as well as functional purposes in the restoration of stained, damaged or defective teeth is well-known in prior art. More recently, dental veneers or facings of ceramic and plastic materials have come into general usage. Unlike crowns, such veneers do not cover all or a major portion of exposed tooth area. Instead, they are generally utilized to provided a cosmetic and/or prosthetic covering for labial and incisal tooth surfaces alone. As will be explored in more detail below, this technique has numerous advantages to the patient.
The evolution of technology for the production and utilization of dental facings can easily be traced by a review of the following selected patents:
______________________________________ D. A. Zurbigg U.S. Pat No. 1,265,022 J. L. P. Roumeguere U.S. Pat No. 1,393,166 S. J. Infante U.S. Pat No. 2,700,822 Faunce U.S. Pat No. 3,986,261 Cohen et al. U.S. Pat No. 4,226,593 McClure U.S. Pat No. 4,552,779 ______________________________________
The first patents in this area involve replaceable facings for use on or with artificial teeth, crowns, or bridgework. (See, e.g., Zurbigg, Roumeguere and Infante, supra). More recently, the Faunce patent discloses a method for restoring tooth surfaces by utilizing a laminar plastic tooth facing adapted for bonding to the enamel of a patient's tooth. This technology has been eagerly adopted within the art, and preformed plastic and ceramic facings of various sizes are now readily available on the market. Cohen sets forth a method and apparatus for applying a plurality of such veneers simultaneously to a patient's teeth. In contrast to these McClure describes a process for preparing a cast metal surface for bonding to tooth structure. This methodology is adapted and explained with reference to the placement and maintenance of bridges for the retention of artificial teeth. It has not been utilized with regard to metallic tooth facings, adapted primarily for placement on the labial surface of a patient's tooth.
Where precious metals are to be utilized, as a covering for the labial surface of the tooth, patients have been generally restricted to emplacement of a crown. This is a procedure that requires the tooth to be extensively shaped by grinding in order to present a shape suitable for reception of the crown. This not only results in the loss of the integrity of the natural tooth, but is expensive and time consuming. Further, many such crowns are placed for cosmetic purposes alone. Thus, a less invasive procedure is highly desirable to preserve the function and superiority of the natural tooth.